During a sit down on stream with a couple of developers for Marvel vs. Capcom: Infinite, a few details were revealed about certain changes to the series' formula. In particular, the change to make it a 2v2 fighter instead of a 3v3 game was to make it feel more team oriented.

The developers felt like having a character selected only as an assist didn't really do someone justice in how they could function in a team. Specifically, it was mentioned that having a character for his/her off the ground assist to help the on point character continue his/her combos didn't really emphasize the team work that well.

Instead of assists, they made it so that tagging in and out with characters can be achieved — even mid combo — to do a better job of emphasizing the teamwork aspect of the characters.

The purpose of the infinity stones was to present a better strategical advantage that a third character isn't able to offer while also emphasizing character identities.

It was mentioned that even if they were to go 4v4 or 5v5, they weren't sure if that was really team work among the characters.

With any fighting game, characters are almost always arranged in a tier list if the game offers a good enough competitive experience. This was another reason why the Infinity Stone system was pushed.

It was emphasized that the Marvel vs. Capcom series is meant to be a very character driven game.

The developers felt that the tools that characters were given made it so that some fighters would just always be better than others.

Whether these attributes were power or mobility, they added the Infinity Stone system to help emphasize the characters a little more. If a fighter were lacking a certain attribute, they would hopefully be able to better supplement it with one of the Infinity Stones.

Of course, the players would also be able to strategize on their own with the stones. Maybe they would prefer to supplement a powerful character with even more power with the Infinity Stone that increases power.

They also mentioned that they are spending a great deal of time to make sure that the game is easy to play with both an arcade stick and a controller. The developers want players to feel like that they don't necessarily have to go out and purchase an expensive arcade stick in order to compete at future Capcom Cup events.

They didn't go into detail about how they are going about doing this, but many fans are speculating that it may be a four button game as a result.

It is noted that players don't have to have a great deal of experience with previous entries of the series to be good at Marvel vs. Capcom: Infinite. This was cited as one of the reasons why the game is called Marvel vs. Capcom: Infinite instead of Marvel vs. Capcom 4.

The developers mention that they aren't going to sacrifice depth of the game for the hardcore audience in return for accessibility. Combofiend is said to be heavily involved in the testing process.

The story is said to be a cinematic story about the the first interactions between the two worlds (Marvel and Capcom). If it wasn't already clear from the game's title, this seems to indicate that this game is a reboot of the series.